FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] This gene encodes a multi-domain protein that is a leucine-rich repeat kinase and a GDP/GTP binding protein. The encoded protein is thought to play a role in the regulation of bone mass. Mice lacking a similar gene showed severe osteopetrosis, increased bone mineralization and decreased bone resorption. [provided by RefSeq, Jan 2017] PHENOTYPE: Mice homozygous for a knock-out allele exhibit preweaning lethality. Mice homozygous for another knock-out allele exhibit severe osteopetrosis. [provided by MGI curators]